In recent years, various kinds of, for example, tapes each using a pressure-sensitive adhesive have been developed as patch preparations for administering a drug into a living organism through the surface of a skin. A drug concentration in the pressure-sensitive adhesive needs to be increased to some extent in order that the drug may be effectively released from the patch preparation to the surface of the skin and may be absorbed in the skin. However, increasing the drug concentration causes the following problem. The drug is brought into a supersaturated state or a crystalline state in the pressure-sensitive adhesive, the anchoring property of the pressure-sensitive adhesive to a support reduces, and hence the pressure-sensitive adhesive remains on the surface of the skin upon removal of the patch preparation from the skin.
To solve such problem, by forming a pressure-sensitive adhesive layer on a support having laminated thereon a nonwoven fabric, a woven fabric, or the like, there has been proposed a patch in which the anchoring property of a pressure-sensitive adhesive to a support is improved and hence the adhesive residue of the pressure-sensitive adhesive is prevented (Patent Literature 1). The patch causes no problem when the pressure-sensitive adhesive layer has an enough thickness to cover the unevenness of the nonwoven fabric or the woven fabric. However, when the thickness of the pressure-sensitive adhesive layer containing a drug is reduced in consideration of the utilization ratio of the drug, the following problem arises. The pressure-sensitive adhesive layer cannot completely cover the unevenness of the nonwoven fabric or the woven fabric, and hence its adhesion to the skin reduces, or conversely, an adhesive residue on the skin is liable to occur.
Patent Literature 2 proposes a technology involving using an isocyanate-based compound as an undercoat agent for the surface of a support to improve the anchoring property of a pressure-sensitive adhesive layer to the support. However, the isocyanate-based compound has so short a pot life that means for, for example, blocking moisture or controlling a reaction temperature to a low temperature is needed. Accordingly, an operation becomes extremely complicated. Further, the isocyanate-based compound has high reactivity, and hence may cause a cross-linking reaction or the like with a pressure-sensitive adhesive to change its pressure-sensitive adhesive properties or may cause a decomposition reaction with a drug depending on the kind of the pressure-sensitive adhesive or the drug. Accordingly, sufficient care needs to be taken upon use of the compound.
Patent Literature 3 proposes that the anchoring property of a pressure-sensitive adhesive layer to a support be improved by: applying a primer composition containing fine particles having an average particle diameter of 100 nm or less onto the surface of the support; and forming the pressure-sensitive adhesive layer on the applied composition. However, the primer composition in the literature is poor in handleability and involves a problem in terms of its dispersibility in a liquid, and hence an additional improvement in anchoring property of a patch preparation has been required.